Spring loaded circuit breaker



March 1967 1.. w. BENNETT ETAL 3,309,433

SPRING LOADED CIRCUIT BREAKER l964 I i L? Filed Dec, 24,

INVENTORS LOWELL W. BENNETT MARSHALL E ROSE IHIHIHIHIIllllllllllHlllll BY CZM ATTORNEY United States Patent 3,309,483 SPRING LOADED CIRCUIT BREAKER Lowell W. Bennett, Derwood, and Marshall E. Rose, Laurel, Md., assignors to the United States of America as represented by th Secretary of the Navy 1 Filed Dec. 24, 1964, Ser. No. 421,136 14 Claims. (Cl. 200-154) This invention relates generally to a circuit breaker, and more particularly to a spring loaded circuit breaker capable of successive use under high contact potentials.

Circuit breakers of the type used for the breaking of high energy circuits have a characteristically short life due to the severe plasma arcs which occur. Complete destruction or fusion welding of the contacts is common Where the break has not been effectively performed. The most common deficiency of existing devices resides in their slow initial reaction time.

Therefore, it is an object of this invention to provide a circuit breaker so constructed as to provide an initial shock or impulse which causes circuit rupture.

Another object of the invention is to provide an economical circuit breaker which may be used for repeated circuit breaking activity with a resultant minimum of maintenance.

A still further object of this invention is to provide an efiicient yet safe circuit breaker wherein the break is very rapid thereby avoiding hazardous fires which often occur during sluggish circuit interruption.

-- Another object of the invention is to provide a fail safe circuit breaker such that in the event of an auxiliary power failure, the circuit breaker will automatically open.

An additional object of the invention is to provide secondary contacts which serve to step down the contact area thereby lessening the are generated by the breaking of the circuit.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings, illustrating one embodiment of the instant invention, wherein:

FIG. 1 is a side elevation, partly in section, showing the circuit breaker in the contact making position;

FIG. 2 is a detail View, partly in section, of the support rod and solenoid; and

FIG. 3 is a detail view of one of the auxiliary contacts.

The spring impulse circuit breaker of the present invention is of the type to be used as an emergency stop 'breaker fora DC are heater power supply. It is contemplated that the device will be'used in circuits where 22,000 amperes is not uncommon and the voltage ranges to 2,200 volts. It is well-known in the art that considerable plasma or ionized air will be generated during such occurrences and the problems of effective circuit breaking are of wide range importance.

Referring to the drawings in more detail, the circuit breaker 1 is shown in contact engaging position in FIG. 1. The rod 2 provides the means for mounting the bus bar 3. This bus bar 3 serves as the electrical connection between the contacts 4 which are connected to any high energy source. The outer portions of the contacts 4 are secured by the brackets 5.

The contact bus bar 3 is mounted on the rod 2 by means of an auxiliary aluminum beam 6 connected to the bus bar 3 through the aluminum bars 7. A spring 8 engages the auxiliary beam 6 so as to resiliently mount the beam and the bus bar 3 with respect to the rod 2. The beam 6 also serves to insure that the connection between the contacts 4 and the bus bar 3 remains fiat by preventing the bending of the bus bar 3. The spring 8 engages a collar 9 which is attached to the shaft 2. A

second collar 10 is rigidly connected to the rod 2 above the bus bar 3 and limits the upward movement of said bar 3 on the rod 2. The collar 10 also serves as an impact device which acts to initially break the connection between the contacts 4 and the bus bar 3. This will later be explained in more detail.

A second spring 11 surrounds a reduced upper portion of the rod 2, as best seen in FIGS. 1 and 2. With the bus bar 3 in engagement with the contacts 4, the spring 11 is compressed between the mounting plate 12, and the enlarged section of the rod 2, as shown in FIG. 1. Attached to this plate is a solenoid 13 which, when energized, attracts a lever 14 (which said lever 14 is pivoted at 15 and mounted on an upright support 16). The lever 14 is adapted to engage in a recess 17 in the rod 2 so as to maintain the rod in its upward or engaged position against the resistance of the springs 8 and 1.1 with the solenoid energized. The lever 14 is shown in phantom in FIG. 2 to illustrate its position after the rod 2 is released upon de-energization of the solenoid 13.

The contacts 4 are structurally supported adjacent their contact ends by the aluminum plates 18. These plates are connected to the mounting plate 12 by the aluminum spacers 19 and the plastic or Glastex insulators 20. A sheet of Transite insulating material21 is mounted between the spacers and the plastic insulators to protect the solenoid 13 and the mounting plate 12 from the plasma flares which result when a circuit isfbroken.

The collar ,10 is spaced a distance above the bus bar 3 when the circuit breaking device is in the position as shown in FIG. 1. This arrangement is such that upon de-energization of the solenoid 13 the spring 8 will drive the rod 2 downwardly, causing the collar 10 to sharply strike the bus bar 3. This reaction provides the necessary impetus for initially breaking the circuit between the bus bar 3 and the contacts 4. The spring 11 then serves to completely remove the bus bar 3 from the area of contact. In practice, the bus bar and the rod assembly fall onto a padded mat, not shown, of rubberized horsehair covered with an asbestos blanket to prevent burning of the horsehair.

An additional feature may be provided which serves to reduce the contact area before the circuit is completely broken. This feature consists of an auxiliary contact indicated by the numeral 22 in FIG. 3. A contact shim 23 is attached to each of the contacts 4. These shims are provided so that the auxiliary contact 22, which has a high temperature tungsten alloy tip 24, may maintain contact with the bus bar 3 for a short period of time after the bus bar 3 has disengaged itself from the contact shims 23. These tips provide a reduction of the area over which plasma may form. They also effectively move the contact breaking points of the bus bar outwardly of the point where the bus bar 3 engages the main contacts 4. This serves the advantageous purpose of moving the portion of the bus bar which may be pitted and scorched by the generated plasma to a point outwardly of the main contact area, thereby increasing the effective life and reducing the maintenance to both the bus bar 3 and the contacts 4.

The auxiliary contact 22 is mounted with the main contact 4 in the bracket 5. The auxiliary contact 22 is provided with a reduced-in-thickness portion 25 along its length to facilitate bending. A spring 26 urges the auxiliary contact in a downward direction.

It is obvious that the bus bar 3 will maintain engagement with the auxiliary tips after the connection with the primary contacts 4, in this embodiment contact shims 23, has been breached.

It can readily be seen that many variations and modifications of the present invention are possible in the or light of the aforementioned teachings, and it will be apparent to those skilled in the art that various changes in form and arrangement of components may be made to suit requirements without departing from the spirit and scope of the invention. It is therefore to be understood that within the scope of the appended claims the instant invention may be practised in a manner otherwise than is specifically described herein.

What is claimed is:

1. A circuit breaker, comprising a pair of contacts,

a bus bar adapted to interconnect said contacts,

a mounting rod,

an impact collar connected to said mounting rod,

a spring resiliently urging the impact collar into engagement with the upper surface of said bus bar and permitting relative motion of said bus bar on said rod, mounting bracket,

second spring positioned on the upper portion of said rod and adapted to resiliently connect said rod with said mounting bracket, solenoid mounted on said mounting bracket, and lever pivoted to said mounting bracket and adapted to be actuated by said solenoid upon energization thereof to engage said rod and to resiliently maintain engagement of said bus bar and said contacts.

2. The invention as recited in claim 1, further comprising a pair of auxiliary contacts each cantilevered to one of said contacts and partially disposed between its associated contact and said bus bar.

3. The invention as related in claim 1, further comprising shielding means disposed between said solenoid and said pair of contacts for protecting said solenoid and said mounting plate against plasma flares upon separation of said pair of contacts and said bus bar.

4. The invention as recited in claim ll, further including means for maintaining electrical contact between said pair of contacts and said bus bar for a period of time subsequent to the separation of said pair of contacts and said bus bar.

5. The invention as set forth in claim 2, further comprising shielding means disposed between said solenoid and said pair of contacts for protecting said solenoid and said mounting plate against plasma flares.

6. The invention as set forth in claim 4, further including shielding means disposed between said solenoid and said pair of contacts for protecting said solenoid and said mounting plate against plasma flares upon separation of said pair of contacts and said bus bar.

7. In a circuit breaker, the combination including a rod having a first collar at the lower end thereof and extending to a reduced shouldered portion, said rod further comprising a recess in the upper portion thereof,

a pair of contacts,

a bus bar slidably mounted on said rod and adapted to interconnect said contacts,

an auxiliary beam connected to said bus bar for preventing the bending thereof,

a second collar rigidly secured to said rod for limiting the downward movement of said rod through said bus bar,

a mounting plate,

a solenoid secured to said mounting plate,

an upright support secured to said mounting plate,

a lever pivotably secured to said upright support and adapted to engage said recess at one end portion thereof and be attracted to said solenoid at the other end portion thereof upon energization of said solenoid so as to prevent longitudinal movement of said rod,

a pair of spacers each connected to one of said contacts,

a pair of insulators each connected to said mounting plate and to one of said spacers,

a first spring disposed about the reduced portion of said rod between said mounting plate and said shoulder, and

a second spring disposed about said rod between said first collar and said auxiliary beam for providing sufficient force for separating said bus bar from said contacts, whereby when said solenoid is de-energized said lever will be disengaged from said rod, said second spring will exert a force on said first collar moving said second collar into engagement with said bus bar with sufficient force to separate said bus bar from said contacts, and said first spring will extend so as to cause further movement of said bus bar away from said contacts.

8. The invention as recited in claim 7, further including means for maintaining electrical contact between said pair of contacts and said bus bar for a period of time subsequent to the separation of said pair of contacts and said bus bar.

9. The invention as related in claim 7, wherein said circuit breaker additionally includes a pair of auxiliary contacts each cantilevered to one of said contacts and partially disposed between its associated contact and said bus bar.

10. The invention as related in claim 8, wherein said circuit breaker additionally comprises shielding means for protecting said solenoid and said mounting plate against plasma flares upon separation of said pair of contacts and said bus bar.

11. The invention as related in claim 9, wherein said circuit breaker additionally comprises shielding means disposed between said solenoid and said pair of contacts for protecting said solenoid and said mounting plate against plasma flares.

12. In a circuit breaker, the combination comprising a rod having a first collar at one end thereof and extending to a reduced shouldered portion, said rod further including a recess in the opposite end portion thereof from said first collar,

a plurality of contacts,

means slidably mounted on said rod and adapted to interconnect said contacts,

means for limiting the movement of said rod through said interconnecting means and away from said contacts,

a mounting plate,

a solenoid secured to said mounting plate,

means movably secured to said mounting plate and adapted to engage said recess in response to energization of said solenoid so as to prevent longitudinal movement of said rod, and

means engaging said rod for providing suflicient energy for separating said contact interconnecting means from said contacts, whereby when said solenoid is de-energized said recess engaging means will be disengaged from said recess, and said separating means will effect rapid separation of said contacts and said contact interconnecting means.

13. The invention as set forth in claim 12, wherein said circuit breaker additionally comprises means for maintaining electrical contact between said plurality of contacts and said contact interconnecting means for a period of time after separation of said contact interconnecting means and said plurality of contacts.

14. The invention as related in claim 12, further comprising a plurality of auxiliary contacts each cantilevered to one of said plurality of contacts and partially disposed between its associated contact and said contact interconnecting means.

(References on following page) UNITED References Cited by the Examiner STATES PATENTS Sperry 200168 Summers et a1. 200-104 5 Burcham 200168 Von Henke 200-154 Huber ZOO-450.5 Prescott 335--131 Bradley 335131 Driesch et a1. 200-404 X ROBERT K. SCHAEFER, Primary Examiner. H. J. HOHAUSER, Assistant Examiner. 

1. A CIRCUIT BREAKER, COMPRISING A PAIR OF CONTACTS, A BUS BAR ADAPTED TO INTERCONNECT SAID CONTACTS, A MOUNTING ROD, AN IMPACT COLLAR CONNECTED TO SAID MOUNTING ROD, A SPRING RESILIENTLY URGING THE IMPACT COLLAR INTO ENGAGEMENT WITH THE UPPER SURFACE OF SAID BUS BAR AND PERMITTING RELATIVE MOTION OF SAID BUS BAR ON SAID ROD, A MOUNTING BRACKET, A SECOND SPRING POSITIONED ON THE UPPER PORTION OF SAID ROD AND ADAPTED TO RESILIENTLY CONNECT SAID ROD WITH SAID MOUNTING BRACKET, A SOLENOID MOUNTED ON SAID MOUNTING BRACKET, AND A LEVER PIVOTED TO SAID MOUNTING BRACKET AND ADAPTED TO BE ACTUATED BY SAID SOLENOID UPON ENERGIZATION THEREOF TO ENGAGE SAID ROD AND TO RESILIENTLY MAINTAIN ENGAGEMENT OF SAID BUS BAR AND SAID CONTACTS. 